This invention relates to a snow removing machine having a structure wherein rotation power of an engine is transmitted through a clutch mechansim to an auger and a blower.
Electromagnetic clutches for working machines have heretofore been known from, for example, Japanese Utility Model Laid-Open Publication No. HEI-2-9332 entitled xe2x80x9cElectromagnetic Clutchxe2x80x9d and Japanese Patent No. 2700620 entitled xe2x80x9cElectromagnetic Connecting Apparatusxe2x80x9d.
The electromagnetic clutch disclosed in Japanese Utility Model Laid-Open Publication No. HEI-2-9332 has a rotor fixedly secured to a rotary shaft via a key. A V-pulley is rotatably mounted to a rotary shaft. An armature is mounted to one side of the V-pulley. The armature is moved into or away from the rotor to provide coupled or uncoupled conditions of the clutch in response to turning-on or turning-off states of a field core which is composed of a yoke and an excitation coil. A detent plate is mounted to an outside area of the field core and is fixedly secured to a stationary part of equipment by means of bolts, thereby precluding the field core involving the yoke from rotating in association with rotation of the rotor. Since, however, the electromagnetic clutch has a structure wherein the detent plate is merely secured to the stationary part of the equipment by the bolts, a frame body is directly suffered with reaction caused when the electromagnetic clutch is turned on/off, inevitably causing vibrations in the equipment.
The electromagnetic coupling device disclosed in Japanese Patent No. 2700620 comprises an electromagnetic spring clutch (electromagnetic clutch) which includes a yoke formed with a detent recess with which a detent pin extending from an equipment body is held in engagement. For this reason, when the electromagnetic clutch is turned on/off, the detent pin extending from the equipment body leaps in the detent recess formed in the yoke, resulting in generation of noise in the equipment.
It is therefore an object of the present invention to provide a snow removing machine which is capable of extending a maintenance cycle and makes a maintenance work easy.
According to an aspect of the present invention, there is provided a snow removing machine which comprises a prime mover, an output shaft for outputting power of the prime mover, an electromagnetic clutch located at a distal end of the output shaft, a drive pulley located at a proximal end of the output shaft, and a snow-removing work section, designed to be driven by power transmitted from the output shaft to the drive pulley and a transmission belt via the electromagnetic clutch, for performing snow-removing work.
Provision of the electromagnetic clutch at the proximal end of the output shaft leads to the advantages that the electromagnetic clutch is kept away from the prime mover to thereby prevent heat generated by the prime mover from being directly transferred to the electromagnetic clutch and an adequate amount of space is provided for easy maintenance of the electromagnetic clutch.
The output shaft is rotatably mounted to a cylinder block of the prime mover via a bearing. Thus, the smaller a bending moment applied to the output shaft becomes, the less a load applied to the bearing becomes. This invention therefore contemplates positioning the drive pulley at the proximal end of the output shaft, that is, an area close to the engine, to make the bending moment applied to the output shaft small to thereby decrease the load applied to the bearing supporting the output shaft.
In a desired form, the electromagnetic clutch comprises a main member coupled to the output shaft for joint rotation with the latter, a submember mounted to the drive pulley in opposed relation to the main member, and a yoke having an excitation coil, the submember being designed to be pulled tightly against the main member upon energization of the excitation coil so that rotational power is transmitted from the main member to the drive pulley. In addition, a detent member is provided to project from the yoke for preventing rotation of the yoke in unison with the main member, the yoke being connected to an anchoring member via a resilient member mounted to the detent member.
With the submember disposed in opposed relation to the main member, the submember, upon energization of the excitation coil, is attracted to or pulled against the main member, whereby rotational power is transmitted from the main member to the submember. When the excitation coil is held in an ON state, the an attracting force is exerted on the yoke which is liable to cause the yoke to rotate in unison with the main member. When the excitation coil is shifted from the ON state to an OFF state, the attracting force applied to the yoke abruptly disappears to thereby make the yoke encounter a reactive or counter movement. Such an action the yoke experiences in response to turning on or turning off of the excitation coil is hereinafter referred to as an xe2x80x9cinterlocking phenomenon of the voicexe2x80x9d. To this end, the detent member extends from the yoke and is provided with the resilient member through which the yoke is connected to the anchoring member forming part of a body frame of the machine. This makes it possible to mitigate the xe2x80x9cinterlocking phenomenon of the yokexe2x80x9d that otherwise occurs when the excitation coil is turned on or turned off. This leads to reduction in vibration or noise arising from an operation of the electromagnetic clutch.
It is desirable that for securing the yoke to the anchoring member, the anchoring member includes a support bracket with a pair of support walls for limiting movement of the detent member, the support walls retaining the resilient member in a sandwiched fashion. As a result, the detent member is held stationary to suppress the interlocking phenomenon, and the resilient member absorbs the reaction that the yoke experiences upon shifting between the turning on and turning off of the coil. Movement of the detent member is suppressed by providing the support walls in such a manner as to sandwich the detent member. Moreover, with the resilient member retained by the support bracket along its entire periphery, vibration of the electromagnetic clutch in all directions can be prevented.